user to purchase two U2F USB keys — not for data storage, but for identity verification. The U2F keys are used to provide two-step verification during login. One is for backup purposes, in case the first is lost. The Advanced Protection Program includes further security measures to protect the user's account, such as restrictions on which applications the user can grant access to their account, and a more thorough identity verification process for regaining access to the account if the password is forgotten. On June 5, 2012, a new security feature was introduced to protect users from state-sponsored attacks. Whenever Google analysis indicate that a government has attempted to compromise an account, a notice will be displayed that reads "Warning: We believe state-sponsored attackers may be trying to compromise your account or computer." Activity tracking The tool called 'My Activity' launched in 2016 - which supersedes Google Search history and Google Web History — enables users to see and delete data tracked by Google through the Google account. The tool shows which websites were visited using Chrome while logged in, devices used, apps used, Google products interacted with, etc. All information is laid out in a timeline-like layout. Users can choose to entirely disable tracking, or remove certain activities which they don't want to be tracked. Account blocking Google may block an account for various reasons, such as "unusual activity" or entering an age "not old enough" to own a Google account. Reactivation is possible using web-forms, providing proof of identity through valid photo ID, or a credit card payment of US$0.30. Other methods (such as sending a fax or uploading some requested document) may require human interaction and may take some "days or a couple of weeks" to be accomplished. See also Apple ID Facebook Platform: Authentication Microsoft account OpenID References External links Account Federated identity